Senior Embedded Firmware Engineer - LoRaWAN & RTOS

Triton Environmental Consultants, Ltd.; Mounds View (MN); On-site; USD 110,000 - 140,000; Full time

Job summary

Triton Environmental Consultants, Ltd. is seeking an experienced firmware engineer to design, develop, and maintain LoRaWAN module firmware and custom sensor applications.

You will work across Mbed OS and Zephyr RTOS targeting STM32 and ARM Cortex-M microcontrollers to deliver production AT command firmware and LoRaWAN Class A/B/C support. The role emphasizes power optimization, secure field updates, porting Zephyr BSPs, and collaboration with hardware teams for new variants and customer

Qualifications

• 5+ years bare-metal and RTOS firmware development on Arm Cortex-M MCUs.
• Strong C/C++ for resource-constrained MCUs.
• LoRaWAN protocol stack experience (MAC, Class A/B/C).
• STM32 family peripherals and low-power modes.
• Mbed OS 6.x development and build processes.
• Zephyr RTOS: device tree, Kconfig, west-based builds.
• SPI/I2C peripherals and RF transceivers (SX1272/ SX1262).
• JTAG/SWD debugging and RF test equipment familiarity.
• Git-based workflows and Jenkins CI/CD pipelines.
• AT command interface design and implementation.

Responsibilities

• Develop and maintain LoRaWAN AT command firmware across hardware variants.
• Own the LoRaWAN MAC layer library — Class A/B/C operation, multicast, FOTA, ADR.
• Implement and validate LoRaWAN specification compliance (Class B timing, ping-slot).
• Port and maintain Zephyr BSPs including board definitions and drivers.
• Develop custom LoRaWAN sensor applications using Mbed OS and Zephyr.
• Bring up new hardware variants and component changes across the product line.
• Design and execute host-based test suites using CppUTest and Zephyr Twister.
• Maintain bootloaders and FOTA infrastructure for secure field updates.
• Optimize power consumption for ultra-low-power sleep modes.
• Support LoRa Alliance technical working group contributions.

Skills

Firmware development

Bare-metal & RTOS

C/C++ for constrained MCUs

LoRaWAN protocol Stack

ARM Cortex-M

Tools

Mbed OS

Zephyr RTOS

STM32 HAL/LL

JTAG/SWD debugging

Git / Jenkins CI

Job description

Triton Environmental Consultants, Ltd. is seeking an experienced firmware engineer to design, develop, and maintain LoRaWAN module firmware and custom sensor applications.

You will work across Mbed OS and Zephyr RTOS targeting STM32 and ARM Cortex-M microcontrollers to deliver production AT command firmware and LoRaWAN Class A/B/C support. The role emphasizes power optimization, secure field updates, porting Zephyr BSPs, and collaboration with hardware teams for new variants and customer